Thought it may be better to create a new post as this may get lost in the 4090 owners threads. For anyone that has a Zotac 4090 ideally the Extreme Airo version as this is what I have can you do a very simple test. Run any game and open something like GPU Z or HWINFO as this bug gets detected in all programs that can report min/max fans speeds.
Now for some reason fan 1 sensor which controls the fan near the ports and center have this extremely tiny spike in RPM reading that doubles the actual reading that happens randomly and often.
Now to start this is the card manually set at 100%, the fans max out at about 3000 RPM.
Now running any game at the stock fan settings the card will be at 30% or about 1100rpm on all fans but check out this tiny little spike on fan 1, if I check at what RPM speed is reported its double the actual reading but look at the fan speed % it never budges, and even with my ear next to the card the fans never ramp up or even attempt to, the card stays quiet. Forgot to change the average on fan 2 but it's max is 30%
Now I have manually set the fan speed to 70%, now when the spike in the graph occurs again check out the RPM, it's doubled again which for this reading it's impossible as it reads at 4600 RPM when the card can't go passed roughly 3000 RPM, but at 70% fan speed the RPM is 2300 RPM but according the the fan 1 reading during that tiny spike is doubled.
It's as it the card during those spikes is adding the two fan speeds together and reporting as double what it really is. Strange as this happens in every program that can read the GPU RPM and report the min/max but the actual fan % never changes just the RPM. Changed the number below on fan 2 to 70% as I left it on the minimum reading.
Now for some reason fan 1 sensor which controls the fan near the ports and center have this extremely tiny spike in RPM reading that doubles the actual reading that happens randomly and often.
Now to start this is the card manually set at 100%, the fans max out at about 3000 RPM.
Now running any game at the stock fan settings the card will be at 30% or about 1100rpm on all fans but check out this tiny little spike on fan 1, if I check at what RPM speed is reported its double the actual reading but look at the fan speed % it never budges, and even with my ear next to the card the fans never ramp up or even attempt to, the card stays quiet. Forgot to change the average on fan 2 but it's max is 30%
Now I have manually set the fan speed to 70%, now when the spike in the graph occurs again check out the RPM, it's doubled again which for this reading it's impossible as it reads at 4600 RPM when the card can't go passed roughly 3000 RPM, but at 70% fan speed the RPM is 2300 RPM but according the the fan 1 reading during that tiny spike is doubled.
It's as it the card during those spikes is adding the two fan speeds together and reporting as double what it really is. Strange as this happens in every program that can read the GPU RPM and report the min/max but the actual fan % never changes just the RPM. Changed the number below on fan 2 to 70% as I left it on the minimum reading.